Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Code for Kernel probes Jump optimization.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright 2017, Anju T, IBM Corp.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <linux/kprobes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/jump_label.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/list.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <asm/kprobes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <asm/ptrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <asm/cacheflush.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <asm/code-patching.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <asm/sstep.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <asm/ppc-opcode.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <asm/inst.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #define TMPL_CALL_HDLR_IDX	\
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 	(optprobe_template_call_handler - optprobe_template_entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #define TMPL_EMULATE_IDX	\
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 	(optprobe_template_call_emulate - optprobe_template_entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #define TMPL_RET_IDX		\
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 	(optprobe_template_ret - optprobe_template_entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #define TMPL_OP_IDX		\
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	(optprobe_template_op_address - optprobe_template_entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #define TMPL_INSN_IDX		\
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	(optprobe_template_insn - optprobe_template_entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) #define TMPL_END_IDX		\
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	(optprobe_template_end - optprobe_template_entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) DEFINE_INSN_CACHE_OPS(ppc_optinsn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) static bool insn_page_in_use;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) static void *__ppc_alloc_insn_page(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	if (insn_page_in_use)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	insn_page_in_use = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	return &optinsn_slot;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) static void __ppc_free_insn_page(void *page __maybe_unused)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	insn_page_in_use = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) struct kprobe_insn_cache kprobe_ppc_optinsn_slots = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	.mutex = __MUTEX_INITIALIZER(kprobe_ppc_optinsn_slots.mutex),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	.pages = LIST_HEAD_INIT(kprobe_ppc_optinsn_slots.pages),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	/* insn_size initialized later */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	.alloc = __ppc_alloc_insn_page,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	.free = __ppc_free_insn_page,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	.nr_garbage = 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61)  * Check if we can optimize this probe. Returns NIP post-emulation if this can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62)  * be optimized and 0 otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) static unsigned long can_optimize(struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	struct pt_regs regs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	struct instruction_op op;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	unsigned long nip = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	 * kprobe placed for kretprobe during boot time
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	 * has a 'nop' instruction, which can be emulated.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	 * So further checks can be skipped.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 		return (unsigned long)p->addr + sizeof(kprobe_opcode_t);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	 * We only support optimizing kernel addresses, but not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	 * module addresses.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	 * FIXME: Optimize kprobes placed in module addresses.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	if (!is_kernel_addr((unsigned long)p->addr))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	memset(&regs, 0, sizeof(struct pt_regs));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	regs.nip = (unsigned long)p->addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	regs.trap = 0x0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	regs.msr = MSR_KERNEL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	 * Kprobe placed in conditional branch instructions are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	 * not optimized, as we can't predict the nip prior with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	 * dummy pt_regs and can not ensure that the return branch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	 * from detour buffer falls in the range of address (i.e 32MB).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	 * A branch back from trampoline is set up in the detour buffer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	 * to the nip returned by the analyse_instr() here.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	 * Ensure that the instruction is not a conditional branch,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	 * and that can be emulated.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 	if (!is_conditional_branch(ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	    analyse_instr(&op, &regs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 			  ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) == 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 		emulate_update_regs(&regs, &op);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 		nip = regs.nip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	return nip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) static void optimized_callback(struct optimized_kprobe *op,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 			       struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	/* This is possible if op is under delayed unoptimizing */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	if (kprobe_disabled(&op->kp))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	preempt_disable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	if (kprobe_running()) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 		kprobes_inc_nmissed_count(&op->kp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 		__this_cpu_write(current_kprobe, &op->kp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 		regs->nip = (unsigned long)op->kp.addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 		get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 		opt_pre_handler(&op->kp, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 		__this_cpu_write(current_kprobe, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	preempt_enable_no_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) NOKPROBE_SYMBOL(optimized_callback);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	if (op->optinsn.insn) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		free_ppc_optinsn_slot(op->optinsn.insn, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		op->optinsn.insn = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)  * emulate_step() requires insn to be emulated as
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)  * second parameter. Load register 'r4' with the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)  * instruction.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) void patch_imm32_load_insns(unsigned int val, kprobe_opcode_t *addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	/* addis r4,0,(insn)@h */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	patch_instruction((struct ppc_inst *)addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 			  ppc_inst(PPC_INST_ADDIS | ___PPC_RT(4) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 				   ((val >> 16) & 0xffff)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	addr++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	/* ori r4,r4,(insn)@l */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	patch_instruction((struct ppc_inst *)addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 			  ppc_inst(PPC_INST_ORI | ___PPC_RA(4) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 				   ___PPC_RS(4) | (val & 0xffff)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164)  * Generate instructions to load provided immediate 64-bit value
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165)  * to register 'reg' and patch these instructions at 'addr'.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) void patch_imm64_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	/* lis reg,(op)@highest */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	patch_instruction((struct ppc_inst *)addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 			  ppc_inst(PPC_INST_ADDIS | ___PPC_RT(reg) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 				   ((val >> 48) & 0xffff)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	addr++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	/* ori reg,reg,(op)@higher */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	patch_instruction((struct ppc_inst *)addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 			  ppc_inst(PPC_INST_ORI | ___PPC_RA(reg) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 				   ___PPC_RS(reg) | ((val >> 32) & 0xffff)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	addr++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	/* rldicr reg,reg,32,31 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	patch_instruction((struct ppc_inst *)addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 			  ppc_inst(PPC_INST_RLDICR | ___PPC_RA(reg) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 				   ___PPC_RS(reg) | __PPC_SH64(32) | __PPC_ME64(31)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	addr++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	/* oris reg,reg,(op)@h */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	patch_instruction((struct ppc_inst *)addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 			  ppc_inst(PPC_INST_ORIS | ___PPC_RA(reg) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 				   ___PPC_RS(reg) | ((val >> 16) & 0xffff)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	addr++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	/* ori reg,reg,(op)@l */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	patch_instruction((struct ppc_inst *)addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 			  ppc_inst(PPC_INST_ORI | ___PPC_RA(reg) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 				   ___PPC_RS(reg) | (val & 0xffff)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	struct ppc_inst branch_op_callback, branch_emulate_step, temp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	kprobe_opcode_t *op_callback_addr, *emulate_step_addr, *buff;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	long b_offset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	unsigned long nip, size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	int rc, i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	kprobe_ppc_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	nip = can_optimize(p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	if (!nip)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 		return -EILSEQ;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	/* Allocate instruction slot for detour buffer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	buff = get_ppc_optinsn_slot();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	if (!buff)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	 * OPTPROBE uses 'b' instruction to branch to optinsn.insn.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	 * The target address has to be relatively nearby, to permit use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	 * of branch instruction in powerpc, because the address is specified
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	 * in an immediate field in the instruction opcode itself, ie 24 bits
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	 * in the opcode specify the address. Therefore the address should
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	 * be within 32MB on either side of the current instruction.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	b_offset = (unsigned long)buff - (unsigned long)p->addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 	if (!is_offset_in_branch_range(b_offset))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 		goto error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	/* Check if the return address is also within 32MB range */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 	b_offset = (unsigned long)(buff + TMPL_RET_IDX) -
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 			(unsigned long)nip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 	if (!is_offset_in_branch_range(b_offset))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 		goto error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 	/* Setup template */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 	/* We can optimize this via patch_instruction_window later */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 	size = (TMPL_END_IDX * sizeof(kprobe_opcode_t)) / sizeof(int);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	pr_devel("Copying template to %p, size %lu\n", buff, size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	for (i = 0; i < size; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 		rc = patch_instruction((struct ppc_inst *)(buff + i),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 				       ppc_inst(*(optprobe_template_entry + i)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 		if (rc < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 			goto error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 	 * Fixup the template with instructions to:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	 * 1. load the address of the actual probepoint
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	patch_imm64_load_insns((unsigned long)op, 3, buff + TMPL_OP_IDX);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	 * 2. branch to optimized_callback() and emulate_step()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	op_callback_addr = (kprobe_opcode_t *)ppc_kallsyms_lookup_name("optimized_callback");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	emulate_step_addr = (kprobe_opcode_t *)ppc_kallsyms_lookup_name("emulate_step");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	if (!op_callback_addr || !emulate_step_addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 		WARN(1, "Unable to lookup optimized_callback()/emulate_step()\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 		goto error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	rc = create_branch(&branch_op_callback,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 			   (struct ppc_inst *)(buff + TMPL_CALL_HDLR_IDX),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 			   (unsigned long)op_callback_addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 			   BRANCH_SET_LINK);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	rc |= create_branch(&branch_emulate_step,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 			    (struct ppc_inst *)(buff + TMPL_EMULATE_IDX),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 			    (unsigned long)emulate_step_addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 			    BRANCH_SET_LINK);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 	if (rc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 		goto error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	patch_instruction((struct ppc_inst *)(buff + TMPL_CALL_HDLR_IDX),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 			  branch_op_callback);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	patch_instruction((struct ppc_inst *)(buff + TMPL_EMULATE_IDX),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 			  branch_emulate_step);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 	 * 3. load instruction to be emulated into relevant register, and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 	temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 	patch_imm64_load_insns(ppc_inst_as_u64(temp), 4, buff + TMPL_INSN_IDX);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 	 * 4. branch back from trampoline
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 	patch_branch((struct ppc_inst *)(buff + TMPL_RET_IDX), (unsigned long)nip, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 	flush_icache_range((unsigned long)buff,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 			   (unsigned long)(&buff[TMPL_END_IDX]));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 	op->optinsn.insn = buff;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) error:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 	free_ppc_optinsn_slot(buff, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 	return -ERANGE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) int arch_prepared_optinsn(struct arch_optimized_insn *optinsn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	return optinsn->insn != NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312)  * On powerpc, Optprobes always replaces one instruction (4 bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313)  * aligned and 4 bytes long). It is impossible to encounter another
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314)  * kprobe in this address range. So always return 0.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) int arch_check_optimized_kprobe(struct optimized_kprobe *op)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) void arch_optimize_kprobes(struct list_head *oplist)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 	struct ppc_inst instr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 	struct optimized_kprobe *op;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 	struct optimized_kprobe *tmp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	list_for_each_entry_safe(op, tmp, oplist, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 		 * Backup instructions which will be replaced
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 		 * by jump address
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 		memcpy(op->optinsn.copied_insn, op->kp.addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 					       RELATIVEJUMP_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 		create_branch(&instr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 			      (struct ppc_inst *)op->kp.addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 			      (unsigned long)op->optinsn.insn, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 		patch_instruction((struct ppc_inst *)op->kp.addr, instr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 		list_del_init(&op->list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) void arch_unoptimize_kprobe(struct optimized_kprobe *op)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 	arch_arm_kprobe(&op->kp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) void arch_unoptimize_kprobes(struct list_head *oplist,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 			     struct list_head *done_list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 	struct optimized_kprobe *op;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 	struct optimized_kprobe *tmp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 	list_for_each_entry_safe(op, tmp, oplist, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 		arch_unoptimize_kprobe(op);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 		list_move(&op->list, done_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) int arch_within_optimized_kprobe(struct optimized_kprobe *op,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) 				 unsigned long addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) 	return ((unsigned long)op->kp.addr <= addr &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) 		(unsigned long)op->kp.addr + RELATIVEJUMP_SIZE > addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) }